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V-Ray for Maya Displacement Tutorial

I learned this the hard way, so here’s my contribution to the Maya / V-Ray community.

So you want to get your Mudbox model displacements into Maya and V-Ray 2.0?
Technically this should be quite simple, but if you’re using a 32-bit EXR, it’s a bit harder. Here’s a very quick and dirty way to get it working. Sorry for not showing step by step images or videos, but I just don’t have time right now. I’ve got a baby in the house, sorry! 😉

Step by step:

1. Export your displacement map from Mudbox using Raycasting or Subdivision. Subdivision is faster, Raycasting is more accurate but takes a while to export. Use 32-bit EXR or 16 bit. You can use 8 bit PNGs or whatever format you want, but to be more accurate, we’re using floating point 32 bit EXRs here.

2. Export your lowest level model from Mudbox as an OBJ file.

3. Import the lower level geometry into Maya.

4. Put a VrayMtl onto the model.

5. Make a file node in the Hypershade, attach it as a displacement node to the VrayMtl.

6. Load your 32 bit EXR into the file node. Turn off filtering!

7. Add a VRay Extra Attribute in the file node called “Allow Negative Colors” ( if using 16 bit, then this step is probably not necessary. Haven’t tested though)

8. Turn on V-ray displacement options on your mesh (Quality+Options, etc) so you can set the values of your displacement.

9. Turn on “Keep Continuity”

10. The default (1 and 0) Displacement Amount and Shift should be correct.

11. If you want to change the Displacement amount and shift, make sure that they are inverted values.
ie. Disp. Amount = 1 then Disp. Shift is -1.

12. Turn on subdivision on the object via the Vray Extra Attributes. Set the value from 256 to the upper level of the mud box hires model. So, if the upper level of your model is 7, then set that to 7 (duh!).

I think you need to add a “Allow Negative Colors” Vray attribute to your displacement file node. Either that or you don’t have Keep continous on in your shape node’s extra vray attributes for displacement control. Chaosgroup’s forum is probably a better place to get help with this. I’m just showing a tutorial on how this is supposed to work.